Methods and apparatus for treating spondylolysis

ABSTRACT

Methods and apparatus provide for coupling a spinous process plate to one lateral side of a spinous process of a spine of a patient; coupling a laminar plate to a laminar on the one lateral side of the spinous process of the spine; engaging a sub-laminar hook to the laminar on the one lateral side of the spinous process; and (iv) extending a rod toward a pedicle on the one lateral side of the spinous process of the spine of the patient, where the rod prohibits movement of bone associated with a fracture in a pars interarticularis of a vertebral arch on the one lateral side of the spinous process of the spine.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. patent application Ser. No.16/781,648, accorded a filing date of Feb. 4, 2020; which claims thebenefit of U.S. Provisional Patent Application No. 62/803,934, filedFeb. 11, 2019, the entire disclosures of which are hereby incorporatedby reference.

BACKGROUND OF THE INVENTION

The present invention relates to methods and apparatus for treatingspondylolysis.

Spondylolysis is a defect or stress fracture in the parsinterarticularis of the vertebral arch. Although the vast majority ofcases occur in the lower lumbar vertebrae of the spine (e.g., L5),spondylolysis may also occur in the cervical vertebrae.

Pars stress fractures involve a small connecting bone in the spine,called the pars interarticularis. The pars bone is a small bone thatconnects the facet joints, the chain of joints found on each side of thespine. The facet joints spread apart and have no pressure on them whenthe patient is sitting or bending forward; however, they press againsteach other and are under pressure during activities such as running,jumping, kicking, rotating or arching backward.

Spondylolysis is a common diagnosis that exists in anywhere from about4-6% of the adolescent (young adult) population. It is believed thatboth repetitive trauma and an inherent genetic weakness can make anindividual more susceptible to spondylolysis. Research supports thatthere are hereditary and acquired risk factors that can make one moresusceptible to spondylolysis. Spondylolysis is generally more prevalentin males compared to females, and tends to occur earlier in males due totheir involvement in more strenuous activities at a younger age. In ayoung athlete, the spine is still growing, which means that there aremany ossification centers, leaving points of weakness in the spine. Thisleaves young athletes at increased risk of spondylolysis, particularlywhen involved in repetitive hyperextension and rotation across thelumbar spine. Spondylolysis is a common cause of low back pain inpreadolescents and adolescent athletes, as it accounts for about 50% ofall low back pain.

The rise in athletic participation, as well as the intensity ofparticipation has led to a growing incidence of these stress fractures.Most of these are treated without surgery but 20% of these requiresurgical intervention. A lot of these are treated by benign neglectprimarily because no great techniques exist to repair this stressfracture. The L4 spondylolysis untreated increases the stress on theL4-5 disc space to 120% and the untreated L5 spondylolysis untreatedincreases the stress on the L5-S1 disc space to 168%. Repair of thelysis returns the stress on the disc caused by the spondylolysis to nearnormal, thereby preventing disc degeneration and back pain.

Significant numbers, perhaps even all of the adult isthmicspondylolisthesis that are fused with pedicle screws and interbodyfusions are essentially adult manifestations of an untreated adolescentspondylolysis. Unfortunately, many of these become symptomatic inadulthood when people have already determined their livelihood. Manytimes after the lumbar fusion for spondylolisthesis, patients do recoverand are markedly improved but may be left with restrictions that preventthem from returning to their profession. Frequently this leads topermanent restrictions and ultimately burdens society and the disabilitysystem.

Current techniques to repair a pars interarticularis stress fractureinclude wires and cables, repair with pedicle screw and a curved rodunder the spinous process, pedicle screws, or a rod hook construct underthe lamina.

Although the conventional techniques may yield some degree ofimprovement, they are crude and have limitations. None of theconventional techniques that presently exist provide sufficientsegmental rigid multi-planar fixation. The conventional techniques alsohave secondary side effects, as they encroach and disrupt neighboringfacet joints. Alteration of the anatomy resulting from the conventionaltechniques may lead to foraminal stenosis and postoperativeradiculopathy. The conventional techniques also require sizable implantsthat may become painful hardware in the young thin gymnast or a thinpatient.

The problems associated with the conventional techniques for repair apars interarticularis stress fracture have led surgeons to shy away fromtreating spondylolysis surgically. The lack of a superior surgicaltechnique has also led to practitioners recommending that patients livewith residual symptoms and refrain from sports or other riskyactivities. The current recommendation for patients with this diagnosisinclude: 1) Elimination of all activities and wear a lumbo-sacralorthosis for three months (if the fracture heals, then the patients mayresume all activities). 2) If the fracture does not heal, avoid certainsports and activities, and consider occupations that avoid manual labor.For patients that have mild residual symptoms, accept the residuals, andfind coping mechanisms. 3) Patients that fail to heal and remainsymptomatic are typically treated surgically.

Accordingly, there are needs in the art for improved methods andapparatus for treating spondylolysis.

SUMMARY OF THE INVENTION

In accordance with one or more embodiments of the invention, methods andapparatus provide for coupling a spinous process plate to one lateralside of a spinous process of a spine of a patient, the spinous processplate extending substantially parallel to a sagittal plane(anterior-posterior plane) through the spine of the patient, the spinousprocess plate including a first fixation element facilitating aconnection of the spinous process plate to the one lateral side of thespinous process.

The methods and apparatus may further provide for coupling a laminarplate to a laminar on the one lateral side of the spinous process of thespine, the laminar plate extending transversely from the spinous processplate and transversely to both the sagittal plane and a coronal plane(lateral plane) through the spine of the patient, the laminar plateincluding a second fixation element facilitating a connection of thelaminar plate to the laminar on the one lateral side of the spinousprocess.

The methods and apparatus may still further provide for engaging asub-laminar hook to the laminar on the one lateral side of the spinousprocess, the sub-laminar hook extending transversely from the laminarplate and substantially parallel to a transverse plane through the spineof the patient, the sub-laminar hook extending and hooking beneath thelaminar on the one lateral side of the spinous process of the spine.

The methods and apparatus may still further provide for extending a rodtoward a pedicle on the one lateral side of the spinous process of thespine of the patient, the rod having proximal and distal ends, theproximal end being connected to the laminar plate and the rod extendingfrom the laminar plate toward the pedicle.

Preferably, the rod prohibits movement of bone associated with afracture in a pars interarticularis of a vertebral arch on the onelateral side of the spinous process of the spine.

The methods and apparatus may still further provide that the firstfixation element includes a first aperture through the spinous processplate and a first anchoring element extending through the first apertureand into the one lateral side of the spinous process, therebyfacilitating the connection of the spinous process plate to the spinousprocess of the spine.

The methods and apparatus may still further provide that the secondfixation element includes a second aperture through the laminar plateand a second anchoring element extending through the second aperture andinto the laminar on the one lateral side of the spinous process, therebyfacilitating the connection of the laminar plate to the laminar of thespine.

The methods and apparatus may still further provide for coupling thedistal end of the rod to the pedicle on the one lateral side of thespinous process of the spine of the patient via a third fixationelement.

The methods and apparatus may still further provide that the thirdfixation element includes a tulip coupled to the pedicle via a pediclescrew, and a locking element fixing the distal end of the rod to thetulip.

The methods and apparatus may still further provide that the spinousprocess plate extends in a first plane, the laminar plate extends in asecond plane, and the first and second planes are at an obtuse anglewith respect to one another.

The methods and apparatus may still further provide that the obtuseangle is one of: (i) between 90 degrees and about 140 degrees; (ii)between 90 degrees and about 130 degrees; (iii) between 90 degrees andabout 120 degrees; (iv) between about 100 degrees and about 120 degrees;and (v) about 110 degrees.

The methods and apparatus may still further provide that the laminarplate includes an axis extending substantially parallel to thetransverse plane of the patient, and the rod includes a longitudinalaxis extending from the laminar plate at an obtuse angle with respect tothe axis.

The methods and apparatus may still further provide that the obtuseangle is one of: (i) between about 120 degrees and about 160 degrees;(ii) between about 130 degrees and about 150 degrees; and (iii) about140 degrees.

The methods and apparatus may still further provide that the spinousprocess plate, the laminar plate, and the rod are sized and shaped toconnect to a lumbar vertebrae of the spine of the patient.

Other aspects, features, and advantages of the present invention will beapparent to one skilled in the art from the description herein taken inconjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

For the purposes of illustration, there are forms shown in the drawingsthat are presently preferred, it being understood, however, that theinvention is not limited to the precise arrangements andinstrumentalities shown.

FIG. 1 is a view of a patient's vertebrae in the transverse plane, wherethe patient suffers from a pars fracture;

FIG. 2 is a posterior view of a model of a lumbar spine on which firstand second pars plate apparatus have been attached to respective levels,in order to simulate surgical treatment of respective pars fractures ateach level;

FIG. 3 is an alternative posterior view of the arrangement of FIG. 2 ;

FIG. 4 is a perspective view of a pars plate apparatus in accordancewith one or more embodiments of the invention;

FIG. 5 is a posterior view of the pars plate apparatus in accordancewith one or more embodiments of the invention;

FIG. 6 is a transverse view of the pars plate apparatus in accordancewith one or more embodiments of the invention;

FIG. 7 is a posterior view of a lumbar spine on which a pars plateapparatus is disposed on a patient's spine in order to treat a parsfracture;

FIG. 8 is an alternative posterior-transverse perspective view of thearrangement of FIG. 7 ;

FIG. 9 is an transverse view of the arrangement of FIG. 7 ; and

FIG. 10 is an anatomical schematic diagram showing the respectivecoronal plane, sagittal plane, and axial (or transverse) plane of thehuman anatomy as used herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings wherein like numerals indicate likeelements there is shown in FIG. 1 a view of a patient's vertebrae 12 inthe transverse (axial) plane, where the patient suffers from a parsfracture 20. As is the general case, the fracture 20 is located in thepars interarticularis, which connects the facet joints at respectivelateral sides of the spinous process 14.

FIG. 2 is a posterior view of a model of a lumbar spine of a patient onwhich a first pars plate apparatus 100A and a second pars plateapparatus 100B have been attached at respective levels. Each of thefirst and second pars plate apparatus 100A, 100B traverse a respectivefracture 20. FIG. 3 is an alternative posterior view of the arrangementof FIG. 2 .

Some details regarding the design and function of the respective firstand second pars plate apparatus 100A, 100B will now be presented withreference to FIGS. 4, 5, and 6 . FIG. 4 is a perspective view of anapparatus 100 in accordance with one or more embodiments of theinvention. FIG. 5 is a posterior view of the pars plate apparatus 100,and FIG. 6 is a transverse view of the pars plate apparatus 100.

The pars plate apparatus 100 includes a spinous process plate 102, alaminar plate 104, a sub-laminar hook 106, and a rod 108. The spinousprocess plate 102, the laminar plate 104, and the rod 108 are sized,shaped, and interoperable to connect to a vertebrae of the spine of thepatient, such as the lumbar spine.

The spinous process plate 102 extends substantially parallel to thesagittal plane (anterior-posterior plane) through a spine of the patientwhen implanted. The spinous process plate 102 includes at least onefirst fixation element 102A facilitating a connection of the spinousprocess plate 102 to one lateral side of the spinous process 14 of thespine. For example, the first fixation element 102A may include a firstaperture through the spinous process plate 102 and a first anchoringelement (such as a nail, screw, or the like) extending through the firstaperture and into the one lateral side of the spinous process 14,thereby facilitating the connection of the spinous process plate 102 tothe spinous process 14 of the spine.

The laminar plate 104 extends transversely from the spinous processplate 102 and transversely to both the sagittal plane and the coronalplane (lateral plane) through the spine of the patient when implanted.The laminar plate 104 includes at least one second fixation element 104Afacilitating a connection of the laminar plate 104 to a laminar on theone lateral side of the spinous process 14 of the spine. For example,the second fixation element 104A may include a second aperture throughthe laminar plate 104 and a second anchoring element (such as a nail,screw, or the like), extending through the second aperture and into thelaminar 16 on the one lateral side of the spinous process 14, therebyfacilitating the connection of the laminar plate 104 to the laminar 16of the spine.

The sub-laminar hook 106 extends transversely from the laminar plate 104and substantially parallel to the transverse (axial) plane through thespine of the patient when implanted. The sub-laminar hook 106 is sizedand shaped to extend and hook beneath the laminar 16 on the one lateralside of the spinous process 14 of the spine.

The rod 108 includes a proximal end 108A and a distal end 108B, theproximal end 108A being connected to the laminar plate 104 and the rodextending from the laminar plate 104 toward a pedicle on the one lateralside of the spinous process 14 of the spine when implanted. The rod 108is sized shaped and anchored (as discussed later) to prohibit movementof bone associated with the fracture 20 in the pars interarticularis ofthe vertebral arch.

Reference is now made to FIGS. 7, 8 and 9 , where FIG. 7 is a posteriorview of the lumbar spine on which the pars plate apparatus 100 isdisposed, FIG. 8 is an alternative posterior-transverse perspective viewof the arrangement of FIG. 7 , and FIG. 9 is an transverse view of thearrangement of FIGS. 7 and 8 . As best seen in FIG. 7 , the pars plateapparatus 100 includes at least one third fixation element 110 couplingthe distal end 108B of the rod 108 to the pedicle on the one lateralside of the spinous process 14 of the spine when implanted. For example,the third fixation element 110 may include a tulip coupled to thepedicle via a pedicle screw, and a locking element fixing the distal end108B of the rod 108 to the tulip.

As best seen in FIGS. 5 and 6 , the spinous process plate 102 extends ina first plane P1, the laminar plate 104 extends in a second plane P2,and the first and second planes P1, P2 are at an obtuse angle A1 withrespect to one another. For example, the obtuse angle A may be one of:(i) between 90 degrees and about 140 degrees; (ii) between 90 degreesand about 130 degrees; (iii) between 90 degrees and about 120 degrees;(iv) between about 100 degrees and about 120 degrees; and (v) about 110degrees.

Also as best seen in FIGS. 5 and 6 , the laminar plate 104 includes anaxis Ax1 extending substantially parallel to the transverse plane of thepatient, and the rod 108 includes a longitudinal axis Ax2 extending fromthe laminar plate 104 at an obtuse angle A2 with respect to the axisAx1. For example, the obtuse angle A2 may be one of: (i) between about120 degrees and about 160 degrees; (ii) between about 130 degrees andabout 150 degrees; and (iii) about 140 degrees.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A method of treating a fracture in a pars interarticularis of avertebral arch on a lateral side of a spinous process of a spine of apatient, the fracture having a length and defining a first part of thefractured pars interarticularis and a second part of the fractured parsinterarticularis, the method, comprising: coupling a spinous processplate to one lateral side of a spinous process of a spine of a patient,the spinous process plate extending substantially parallel to a sagittalplane through the spine when implanted, the spinous process plateincluding a first fixation element configured to pass through thespinous process plate and into the lateral side to attach the spinousprocess plate to the lateral side when implanted; coupling a laminarplate to a laminar on the one lateral side of the spinous process of thespine, the laminar plate extending transversely from the spinous processplate and transversely to both the sagittal plane and a coronal planethrough the spine when implanted, the laminar plate including a secondfixation element configured to pass through the laminar plate and into alaminar to attach the laminar plate to the laminar on the lateral sidewhen implanted; engaging a sub-laminar hook to the laminar on the onelateral side of the spinous process, the sub-laminar hook extendingtransversely from the laminar plate and substantially parallel to atransverse plane through the spine when implanted, the sub-laminar hookconfigured to extend and hook beneath the laminar on the lateral sideand abut the first part of the fractured pars interarticularis; andextending a rod toward a pedicle on the one lateral side of the spinousprocess of the spine of the patient, the rod having proximal and distalends, the proximal end being connected to the laminar plate and the rodextending substantially perpendicular to the length of the fracture fromthe laminar plate toward a pedicle on the lateral side when implanted,wherein the rod is anchored at the distal end to a third fixationelement extending substantially perpendicular to a longitudinal axis ofthe rod in a configuration that couples the distal end of the rod to thesecond part of the fractured pars interarticularis and causes thesub-laminar hook and the rod to prohibit movement of the first andsecond parts of the fractured pars interarticularis relative to oneanother when implanted.
 2. The method of claim 1, wherein the spinousprocess plate includes a first aperture and the first fixation elementincludes a first anchoring element extending through the first apertureand configured to extend into the lateral side, thereby facilitating theattachment of the spinous process plate to the spinous process whenimplanted.
 3. The method of claim 1, wherein the laminar plate includesa second aperture and the second fixation element includes a secondanchoring element extending through the second aperture and configuredto extend into the laminar on the lateral side, thereby facilitating theattachment of the laminar plate to the laminar when implanted.
 4. Themethod of claim 1, wherein the third fixation element couples the distalend of the rod to the pedicle on the lateral side when implanted.
 5. Themethod of claim 4, wherein the third fixation element includes a tulipconfigured to couple to the pedicle via a pedicle screw when implanted,and a locking element fixing the distal end of the rod to the tulip. 6.The method of claim 1, wherein the spinous process plate extends in afirst plane, the laminar plate extends in a second plane, and the firstand second planes are at an obtuse angle with respect to one another. 7.The method of claim 6, wherein the obtuse angle is one of: (i) between90 degrees and about 140 degrees; (ii) between 90 degrees and about 130degrees; (iii) between 90 degrees and about 120 degrees; (iv) betweenabout 100 degrees and about 120 degrees; and (v) about 110 degrees. 8.The method of claim 1, wherein the laminar plate includes an axisconfigured to extend substantially parallel to the transverse plane ofthe patient when implanted, and the rod includes a longitudinal axisextending from the laminar plate at an obtuse angle with respect to theaxis.
 9. The method of claim 8, wherein the obtuse angle is one of: (i)between about 120 degrees and about 160 degrees; (ii) between about 130degrees and about 150 degrees; and (iii) about 140 degrees.
 10. Themethod of claim 1, wherein the spinous process plate, the laminar plate,and the rod are sized and shaped to connect to a lumbar vertebrae of thespine.